Air cleaners and purifiers are widely used for removing foreign substances from the air. The foreign, substances can include pollen, dander, smoke, pollutants, dust, etc. In addition, an air cleaner can be used to circulate room air. An air cleaner can be used in many settings, including at home, in offices, workrooms, etc.
One type of air cleaner is an electrostatic precipitator. An electrostatic precipitator operates by creating a high-voltage electrical field, typically in excess of 5,000 volts. Dirt and debris in the air becomes ionized when it is brought into this high voltage electrical field by an airflow. Charged plates or electrodes in the electrostatic precipitator air cleaner, such as positive and negative plates or positive and grounded plates, create the electrical field and one of the electrode polarities attracts the ionized dirt and debris. Periodically, the electrostatic precipitator can be removed and cleaned. Because the electrostatic precipitator comprises electrodes or plates through which airflow can easily and quickly pass, only a low amount of energy is required to provide airflow through the electrostatic precipitator. As a result, foreign objects in the air can be efficiently and effectively removed.
The electrostatic precipitator is connected to a high voltage power supply that places a high voltage across the charge and collection plates of the electrostatic precipitator. The high voltage employed in a typical electrostatic precipitator presents a significant danger of arcing, shorting, and electrical shock. Arcing can occur when the electrostatic precipitator has been removed from the air cleaner but the high operating voltage supplied to the electrostatic precipitator is still present on the contacts or connectors of the electrostatic precipitator receptacle. Likewise, when an access door is open, a person can bring foreign objects (such as tools) into the air cleaner and can short across the components of the electrostatic precipitator (or across electrical supply points to the electrostatic precipitator). Further, a person can touch components of the electrostatic precipitator or can touch the electrical supply points and can suffer an electrical shock.
One prior art safety measure is shown in U.S. Patent Publication No. 2003/0209420 to Taylor et al. The Taylor publication provides an interlock post 204 that fits down into an interlock recess 206 in order to actuate a switch (see FIG. 3C of the Taylor publication). As a result, electrical power to the unit 200 is disabled when the interlock post 204 leaves the interlock recess 206. This safety measure is meant to insure that electrical power is removed from the unit 200 during any manner of cleaning or servicing operation.
However, this prior art approach has drawbacks. The switch of the Taylor publication is accessible to a person and can be circumvented. A suitable pointed object can be used to actuate the switch even when second electrodes 242 are present. A suitable pointed object can be used to actuate the switch when the second electrodes 242 are not fully inserted into position. Consequently, the device disclosed in the Taylor publication can be powered and can present a danger of contact and electrical shock.
The prior art does not provide more that one switch in order to prevent contact with electrified portions of the air cleaner. The prior art does not prevent the air cleaner from being powered up when the electrostatic precipitator cell is not in position or when the access door is not fully closed.